This invention concerns collection systems for receiving machine tool coolant collected to be filtered and recirculated to the tools. In production, machine tools are typically arranged in transfer lines. Coolant is directed at the cutting tools during machining to cool and lubricate the tools and flush chips and abrading grit away from the part. The coolant is allowed to drain into a floor trench, passing beneath the series of machine tools along with the chips and other solid debris from the machining operation. The liquid in the trench flows along an incline to carry the debris to a settling tank and filter systems, flow nozzles spaced along the trench aiding the flow of debris and insuring there is sufficient volume of liquid to move debris along the trench. The coolant is filtered and recirculated to the machine tools, while the chips are collected for disposal.
The velocity trenches have conventionally been installed below floor level to provide sufficient volume capacity for the accumulated coolant collected progressively from all of the machine tools arranged over and along the velocity trench. The below grade trenches also minimize the spillage of coolant on the floor around the machine tools.
This type of system increases the overall cost of a particular machine tool installation, but also renders it difficult to reconfigure. Also, it would sometimes be desirable to move the installation to another location in the plant or to another site completely. The existence of below grade trenching would make this costly or entirely unfeasible.
Overhead coolant collection piping systems have been devised to overcome this disadvantage, but these systems require large capacity piping and vacuum or pumping circulation systems, which are more complex than the gravity flow trench systems.
Another difficulty involves the flow nozzles which direct jets of clean coolant to the coolant flowing in the trench to insure that chips are carried along with the flow. Where there is an adequate volume of coolant draining from the machine tools, an excess volume of clean coolant is diverted to the flow nozzles than is necessary to keep the debris from accumulating in the trench.
Excessive velocity of the coolant also contributes to "misting" in which atomized liquid drifts out of the trenches and condenses on adjacent surfaces.
It is an object of the present invention to provide a machine tool coolant collection system which does not require below grade trenching and minimizes spillage of the coolant onto the adjacent floor surfaces, as well as misting.
It is another object of the present invention to provide such a collection system which uses flow nozzles supplied with an efficiently controlled diversion of clean coolant to the flow nozzles.